It's a really interesting space to research for economists or political scientists. It's also a lever to turn government, social, financial and other systems into software.
All that to say, yes, PoW and PoS are not necessarily tied to blockchains or DLTs.
You can use PoW as a sort of captcha, for example. If it costs a little bit of CPU to submit a request to a website it's not a big deal for a human. However, if you're running a bot-net suddenly it starts to hurt!